If God exists, and He wants all people to believe in Him, why doesn't He just prove that He exists? If He gave us all a clear sign, would anyone cease to believe?
Let's suppose for a moment that God decided to give you, the reader, a sign that He exists. That might satisfy you, but what about the billions of others in the world? If this is the way God works, showing signs to some and hiding them from others, then who's to say that's not already going on and you just happen to not be one of those fortunate people?
We will have to go further. To answer our skepticism, we will have to suppose that God has decided to reveal Himself to all people everywhere. Now, to achieve this kind of revelation, and to make sure nobody misses the sign, it seems that God would have to give various kinds of signs at every moment of every day. After all, not everyone is paying attention to the same kinds of things at exactly the same time.
Let's think about this. What would happen if God displayed signs for all people every day? What would happen is that we would call it nature. We would rightly study them, explore them, and occasionally be amazed by them, but we would wrongly fail to attribute any sort of divine message to them.
Could it be that this is what is happening every day? Could it be that there is a God, as Jesus taught, who causes the sun to rise and the rain to fall on all people?
But perhaps someone will think that sending sun and rain is not much of a message. I have a feeling we would see the magic of it if God only revealed these things to us individually. But let's put that aside for a moment, because this God that Jesus reveals is also a God who reveals Himself in very personal ways. He reveals Himself more fully to some people than to others. Is this fair? Absolutely, because these personal messages are never meant for the recipients alone. These messages are meant to be shared with the world. And they have been. The question is whether we will accept these messages given to prophets and apostles or whether we will demand a sign for our eyes only.
We cannot have it both ways. Either we want a God who reveals Himself equally to everyone, or we want a God who reveals Himself to certain people more directly than others. If we choose the first option, then we can't complain that the sign is nothing "special." If we choose the second, then we can't complain if we are not a prophet.
Fortunately, we do not have to choose between the two. God has done both. We have just to open our eyes to the impossible occurances that unfold around us every day (i.e. nature). And if we can learn to see that, perhaps we can begin to trust those who tell us that they have seen "even greater things than these."
"Who has believed our message, and to whom has the arm of the Lord been revealed?"
- The Prophet Isaiah (53:1)